The present invention relates to an endoscopic treatment instrument having a flexible tube which is to be inserted into or removed from a treatment instrument insertion channel in an endoscope.
Cannula tubes and papillotomy knives are treatment instruments of such a type that after being passed through a treatment instrument insertion channel in a duodenum fiberscope, their distal end is inserted into the bile or pancreatic duct for examination purposes. To use these treatment instruments, the direction in which the distal end portion projects beyond the endoscope must be subtly controlled so that it is suitable for insertion into the bile and pancreatic ducts.
Conventionally, as typically described in Examined Japanese Utility Model Publication (kokoku) No. 15362/1989, the need has been met by making the flexible tube predisposed to bend in arcuate form in the area of the treatment instrument which is to be located within the curved area of the endoscope in a use mode where said flexible tube is inserted into the treatment instrument insertion channel extending through the endoscope.
In a use mode, the bend-prone area of the flexible tube follows the curvature of the treatment instrument insertion channel in the curved area of the endoscope to regulate the directionality of its distal end portion.
A problem with this design is that the arcuate bend-prone area of the flexible tube often deforms as the flexible tube is passed from the entrance to the exit of the treatment instrument insertion channel and, as a result, the bend will either change direction or become less sharp.
If this occurs, the direction in which the distal end portion of the flexible tube projects beyond the endoscope during examination varies on each occasion, making it impossible for the doctor to insert the treatment instrument smoothly into the bile or pancreatic duct.
An object, therefore, of the invention is to provide such an endoscopic treatment instrument that the distal end portion of a flexible tube extending through the treatment insertion channel in an endoscope can be positively adjusted to project from the endoscope in a desired direction.
The endoscopic treatment instrument of the invention is characterized in that that part of a flexible tube which is to be located within a curved area of an endoscope in a use mode where the flexible tube is inserted into a treatment instrument insertion channel in an endoscope has a cross-sectional shape that promotes bending of that part of the flexible tube in a specified direction. With this design, the distal end portion of the flexible tube which has been passed through the treatment instrument insertion channel of the endoscope can be positively adjusted to project in a desired direction.
The present invention provides, as a preferred embodiment, an endoscopic treatment instrument having a flexible tube which is to be inserted into or removed from a treatment instrument insertion channel extending through the inserting section of an endoscope, said flexible tube being such that the part which is to be located within a curved area formed in the distal end portion of said inserting section in a use mode where said flexible tube is inserted into said treatment instrument insertion channel has a flattened or notched cross-sectional shape.
The flattened cross-sectional shape of the flexible tube may be elliptical or prolate. The notched cross-sectional shape may be formed by partially reducing the wall thickness of the flexible tube in a specified direction.
If desired, that part of the flexible tube which is to be located closer to the distal end than the part that is to be located within the curved area may be formed to have a flattened or notched cross-sectional shape which is twisted from the part to be located within the curved area.
A distal end treating member that is exposed on the outer surface of the flexible tube may be provided in that part of the flexible tube which is to be located closer to the distal end than the part to be located within the curved area.
An adjacent part of the flexible tube, which is closer to the distal end of the flexible tube than the part located within a curved area in the use mode may also have a flattened or notched cross-sectional shape.
The present disclosure relates to the subject matter contained in Japanese patent application Nos. 2000-262228 (filed on Aug. 31, 2000) and 2000-335972 (filed on Nov. 2, 2000), which are expressly incorporated herein by reference in their entireties.